Alert archive / Virginia / Roanoke County
Weather alerts in Roanoke County, Virginia, 2009
125 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Roanoke County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 125
- Warnings
- 36
- Watches
- 19
- Advisories
- 31
- Busiest month
- May24 alerts
- Busiest day
- June 3, 20095 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 1 tornado warnings covering Roanoke County in 2009 had a tornado report inside them.
Roanoke County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 17 | 11 | 35% | 3 | 33% | 4 min |
| Flash flood warnings | 7 | 3 | 57% | 4 | 75% | 109 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Blacksburg, VA: tornado warnings | 19 | 1 | 95% | 9 | 11% | 4 min |
| NWS Blacksburg, VA: severe thunderstorm warnings | 264 | 144 | 45% | 348 | 82% | 26 min |
| NWS Blacksburg, VA: flash flood warnings | 108 | 53 | 51% | 135 | 81% | 100 min |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
Every alert, in the order issued. Times are local, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 7, 4:19 AM EST | Wind Advisory | RNK | 23 hr |
| Jan 15, 4:19 AM EST | Wind Chill Advisory | RNK | 33 hr |
| Jan 25, 2:05 PM EST | Winter Storm Watch | RNK | 25 hr |
| Jan 26, 3:20 PM EST | Winter Weather Advisory | RNK | 45 hr |
| Jan 27, 3:48 PM EST | Wind Advisory | RNK | 29 hr |
| Feb 3, 4:01 AM EST | Winter Weather Advisory | RNK | 32 hr |
| Feb 10, 3:01 PM EST | High Wind Watch | RNK | 14 hr |
| Feb 11, 4:40 AM EST | High Wind Warning | RNK | 35 hr |
| Feb 11, 4:40 AM EST | Wind Advisory | RNK | 43 hr |
| Feb 11, 5:32 PM EST | Mesoscale Discussion | SPC | 88 min |
| Feb 11, 5:53 PM EST | Severe Thunderstorm Watch | SPC | 4 hr |
| Feb 11, 7:24 PM EST | Severe Thunderstorm Warning | RNK | 66 min |
| Feb 11, 8:00 PM EST | Mesoscale Discussion | SPC | 60 min |
| Feb 18, 1:05 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Feb 18, 1:42 PM EST | Wind Advisory | RNK | 38 hr |
| Feb 28, 5:24 AM EST | Winter Storm Watch | RNK | 23 hr |
| Mar 1, 4:39 AM EST | Winter Storm Warning | RNK | 28 hr |
| Mar 1, 4:39 AM EST | Winter Weather Advisory | RNK | 28 hr |
| Mar 1, 1:16 PM EST | Mesoscale Discussion | SPC | 3 hr |
| Mar 2, 3:32 PM EST | Wind Chill Advisory | RNK | 17 hr |
| Mar 13, 9:00 PM EDT | Freezing Rain Advisory | RNK | 12 hr |
| Mar 27, 4:12 AM EDT | Dense Fog Advisory | RNK | 6 hr |
| Mar 29, 4:10 AM EDT | Wind Advisory | RNK | 29 hr |
| Apr 2, 4:17 AM EDT | Dense Fog Advisory | RNK | 5 hr |
| Apr 2, 9:54 PM EDT | High Wind Watch | RNK | 6 hr |
| Apr 3, 3:57 AM EDT | High Wind Warning | RNK | 29 hr |
| Apr 3, 3:57 AM EDT | Wind Advisory | RNK | 32 hr |
| Apr 10, 4:42 PM EDT | Mesoscale Discussion | SPC | 63 min |
| Apr 16, 2:42 PM EDT | Frost Advisory | RNK | 17 hr |
| Apr 21, 2:12 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 22, 1:14 PM EDT | Wind Advisory | RNK | 8 hr |
| Apr 25, 2:46 PM EDT | Mesoscale Discussion | SPC | 59 min |
| May 3, 10:41 PM EDT | Special Weather Statement | RNK | 64 min |
| May 3, 10:43 PM EDT | Flood Watch | RNK | 13 hr |
| May 4, 12:44 AM EDT | Special Weather Statement | RNK | 61 min |
| May 4, 12:29 PM EDT | Tornado Watch | SPC | 5 hr |
| May 6, 1:07 PM EDT | Special Weather Statement | RNK | 53 min |
| May 8, 3:51 PM EDT | Flood Watch | RNK | 26 hr |
| May 8, 10:01 PM EDT | Tornado Watch | SPC | 4 hr |
| May 8, 11:37 PM EDT | Mesoscale Discussion | SPC | 53 min |
| May 9, 4:44 AM EDT | Special Weather Statement | RNK | 46 min |
| May 9, 6:35 AM EDT | Special Weather Statement | RNK | 55 min |
| May 15, 8:26 AM EDT | Areal Flood Warning | RNK | 6 hr |
| May 16, 1:54 PM EDT | Special Weather Statement | RNK | 51 min |
| May 18, 3:57 AM EDT | Frost Advisory | RNK | 29 hr |
| May 26, 12:07 PM EDT | Flash Flood Watch | RNK | 20 hr |
| May 26, 8:05 PM EDT | Special Weather Statement | RNK | 55 min |
| May 26, 9:06 PM EDT | Special Weather Statement | RNK | 54 min |
| May 28, 3:15 PM EDT | Severe Thunderstorm Warning | RNK | 60 min |
| May 28, 3:25 PM EDT | Areal Flood Advisory | RNK | 84 min |
| May 28, 9:41 PM EDT | Severe Thunderstorm Warning | RNK | 64 min |
| May 28, 10:45 PM EDT | Flash Flood Warning | RNK | 2 hr |
| May 28, 10:49 PM EDT | Severe Thunderstorm Warning | RNK | 41 min |
| May 29, 2:45 PM EDT | Special Weather Statement | RNK | 60 min |
| May 31, 2:54 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 31, 3:11 AM EDT | Special Weather Statement | RNK | 94 min |
| Jun 2, 6:25 PM EDT | Severe Thunderstorm Warning | RNK | 37 min |
| Jun 3, 1:06 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 3, 1:51 PM EDT | Flash Flood Watch | RNK | 15 hr |
| Jun 3, 4:02 PM EDT | Severe Thunderstorm Warning | RNK | 58 min |
| Jun 3, 4:34 PM EDT | Mesoscale Discussion | SPC | 86 min |
| Jun 3, 7:10 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Jun 4, 4:48 AM EDT | Flood Watch | RNK | 31 hr |
| Jun 4, 12:39 PM EDT | Severe Thunderstorm Warning | RNK | 66 min |
| Jun 9, 2:31 PM EDT | Mesoscale Discussion | SPC | 89 min |
| Jun 9, 6:09 PM EDT | Severe Thunderstorm Warning | RNK | 81 min |
| Jun 10, 3:46 PM EDT | Severe Thunderstorm Warning | RNK | 59 min |
| Jun 10, 3:52 PM EDT | Tornado Warning | RNK | 38 min |
| Jun 10, 3:55 PM EDT | Severe Thunderstorm Warning | RNK | 53 min |
| Jun 11, 10:47 AM EDT | Special Weather Statement | RNK | 58 min |
| Jun 11, 3:47 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 11, 6:47 PM EDT | Severe Thunderstorm Warning | RNK | 73 min |
| Jun 13, 11:39 AM EDT | Special Weather Statement | RNK | 36 min |
| Jun 16, 2:58 PM EDT | Flash Flood Watch | RNK | 29 hr |
| Jun 16, 10:36 PM EDT | Special Weather Statement | RNK | 54 min |
| Jul 17, 9:42 AM EDT | Severe Thunderstorm Warning | RNK | 63 min |
| Jul 20, 6:00 AM EDT | Special Weather Statement | RNK | 60 min |
| Jul 20, 7:36 AM EDT | Flash Flood Warning | RNK | 4 hr |
| Jul 20, 9:27 AM EDT | Flash Flood Watch | RNK | 12 hr |
| Jul 23, 12:10 AM EDT | Flash Flood Warning | RNK | 5 hr |
| Jul 27, 2:23 AM EDT | Flash Flood Warning | RNK | 2 hr |
| Aug 4, 3:07 PM EDT | Severe Thunderstorm Warning | RNK | 53 min |
| Aug 5, 3:48 PM EDT | Severe Thunderstorm Warning | RNK | 36 min |
| Aug 5, 5:21 PM EDT | Special Weather Statement | RNK | 54 min |
| Aug 5, 5:26 PM EDT | Severe Thunderstorm Warning | RNK | 53 min |
| Aug 5, 6:02 PM EDT | Flash Flood Warning | RNK | 3 hr |
| Aug 10, 1:12 PM EDT | Special Weather Statement | RNK | 33 min |
| Aug 11, 1:03 PM EDT | Mesoscale Discussion | SPC | 87 min |
| Aug 17, 4:29 PM EDT | Special Weather Statement | RNK | 61 min |
| Aug 17, 4:36 PM EDT | Severe Thunderstorm Warning | RNK | 26 min |
| Aug 20, 2:27 PM EDT | Severe Thunderstorm Warning | RNK | 63 min |
| Aug 21, 11:54 PM EDT | Flash Flood Warning | RNK | 6 hr |
| Sep 25, 3:45 PM EDT | Flash Flood Watch | RNK | 31 hr |
| Sep 26, 4:16 PM EDT | Flash Flood Warning | RNK | 6 hr |
| Sep 28, 1:00 PM EDT | Special Weather Statement | RNK | 45 min |
| Oct 6, 9:53 PM EDT | Wind Advisory | RNK | 18 hr |
| Oct 9, 9:47 PM EDT | Special Weather Statement | RNK | 58 min |
| Oct 18, 10:25 AM EDT | Frost Advisory | RNK | 24 hr |
| Oct 19, 3:27 AM EDT | Frost Advisory | RNK | 31 hr |
| Nov 3, 1:44 PM EST | Frost Advisory | RNK | 17 hr |
| Nov 11, 9:36 PM EST | Special Weather Statement | RNK | 114 min |
| Nov 12, 5:12 AM EST | Areal Flood Warning | RNK | 14 hr |
| Nov 12, 8:17 AM EST | River Flood Warning | RNK | 13 hr |
| Nov 12, 7:08 PM EST | Areal Flood Warning | RNK | 6 hr |
| Nov 26, 4:22 AM EST | Wind Advisory | RNK | 48 hr |
| Dec 1, 2:58 PM EST | Wind Advisory | RNK | 45 hr |
| Dec 3, 12:16 AM EST | Special Weather Statement | RNK | 59 min |
| Dec 4, 3:57 PM EST | Winter Weather Advisory | RNK | 27 hr |
| Dec 8, 5:11 AM EST | Wind Advisory | RNK | 64 hr |
| Dec 9, 6:46 AM EST | Areal Flood Warning | RNK | 12 hr |
| Dec 12, 4:41 AM EST | Winter Weather Advisory | RNK | 31 hr |
| Dec 13, 4:16 PM EST | Areal Flood Warning | RNK | 12 hr |
| Dec 13, 8:05 PM EST | Dense Fog Advisory | RNK | 13 hr |
| Dec 17, 4:30 AM EST | Winter Storm Watch | RNK | 11 hr |
| Dec 17, 3:20 PM EST | Winter Storm Warning | RNK | 60 hr |
| Dec 18, 1:32 PM EST | Mesoscale Discussion | SPC | 4 hr |
| Dec 18, 7:22 PM EST | Mesoscale Discussion | SPC | 5 hr |
| Dec 23, 3:49 PM EST | Winter Storm Watch | RNK | 24 hr |
| Dec 24, 4:04 AM EST | Ice Storm Warning | RNK | 35 hr |
| Dec 24, 4:04 AM EST | Freezing Rain Advisory | RNK | 35 hr |
| Dec 24, 4:17 AM EST | Wind Advisory | RNK | 36 hr |
| Dec 24, 11:11 PM EST | Mesoscale Discussion | SPC | 6 hr |
| Dec 25, 6:31 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Dec 30, 3:22 PM EST | Winter Weather Advisory | RNK | 21 hr |
| Dec 30, 10:57 PM EST | Mesoscale Discussion | SPC | 6 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.